GIS Partial Discharge Detection Device and Method Based on LC Wireless Passive Sensor

Abstract

The present invention provides a GIS partial discharge detection device and method based on an LC wireless passive sensor. The device includes an LC sensor and a readout circuit that perform energy coupling and signal transmission through inductive coupling. The LC sensor receives energy from the swept-frequency signal of the readout coil through strong magnetic coupling, thereby generating an induced voltage across the coil ends. The induced voltage passes through a filter circuit to control the capacitance of a varactor diode, causing the resonance frequency of the LC sensor probe to change in a periodic cycle, so as to obtain an LC sensor resonance frequency range that covers the frequency range of partial discharge ultra-high frequency signals. When the resonance frequency of the LC sensor probe is consistent with the partial discharge ultra-high frequency signal, the output signal with the maximum amplitude can be obtained in the readout circuit. By analyzing the amplitude and frequency of the obtained induced voltage, information such as the occurrence of partial discharge, discharge type, and location can be detected. The present invention is small in size, strong in anti-interference ability, simple in structure, and does not require an external power supply, and can be installed inside GIS equipment.

Description

Technical Field

[0001] The present invention relates to LC sensor technology, and particularly to a GIS (Gas Insulated Substation) partial discharge detection device and method based on an LC (inductor-capacitor) wireless passive sensor, belonging to the technical field of measurement and testing. Background Art

[0002] Gas Insulated Substations (GIS) are widely used in high-voltage and extra-high-voltage power transmission systems. GIS equipment has high reliability. However, once a fault occurs inside the GIS equipment, the characteristics of strong enclosure and complex internal structure of the GIS equipment make it difficult for people to accurately locate and determine the fault position.

[0003] Among all types of faults that occur in GIS equipment, faults caused by insulation problems are the most common. Partial discharge is an important factor inducing insulation deterioration and even insulation faults in GIS equipment. Partial discharge in GIS equipment usually refers to the surface flashover along the surface of the pot insulator due to its defects, which will further deepen the deterioration degree of its surface and thus trigger insulation faults.

[0004] The existing GIS partial discharge detection methods mainly include ultrasonic detection method and ultra-high frequency detection method. The ultrasonic detection method is greatly interfered by external noise. Vibration in the environment will bring huge noise, making the vibration caused by partial discharge be submerged by the noise. While the ultra-high frequency method is limited by the large size of the detection antenna and problems such as electrical connection, it cannot be placed inside the GIS box for measurement. Therefore, the detected partial discharge signal is weak and is greatly interfered by external noise. Therefore, a GIS partial discharge detection technology and method with strong anti-interference ability, capable of internal real-time measurement and compatible installation method is needed. Summary of the Invention

[0005] Technical Problem: The object of the present invention is to provide a GIS partial discharge detection device and method based on an LC wireless passive sensor in view of the deficiencies of the above background art, realizing real-time detection of partial discharge in GIS, improving the anti-interference ability of partial discharge detection, and solving the problem that only single-frequency discharge signals can be detected in traditional detection methods.

[0006] Technical Solution:

[0007] A GIS partial discharge detection device based on an LC wireless passive sensor of the present invention adopts the following structure:

[0008] The device includes two parts: an LC sensor probe and a readout circuit. The LC sensor probe and the readout circuit perform energy coupling and signal transmission through inductive coupling. The filter circuit controls the LC sensor probe, and the signal processing circuit controls the readout circuit. The LC sensor probe (2) is installed inside the GIS metal box, and the readout circuit (1) is installed on the rubber sealing ring of the GIS.

[0009] The readout circuit is composed of a signal processing circuit and an inductance coil connected in parallel.

[0010] The LC sensor probe is formed by connecting an inductance coil, a voltage-controlled varactor diode, and a filter circuit in parallel.

[0011] The GIS partial discharge detection device based on the LC wireless passive sensor of the present invention is characterized in that, based on the principle of strong magnetic coupling, when a partial discharge occurs inside the GIS, only by detecting the induced voltage of the LC sensor probe can the occurrence of the partial discharge and the frequency and amplitude of the signal generated thereby be detected, and then the discharge type of the partial discharge can be obtained by comparison.

[0012] The specific detection method is as follows:

[0013] Step 1: The external readout coil emits a frequency-swept signal with energy, which is coupled to the inductance coil of the LC sensor. When the frequency of the signal emitted by the readout coil is consistent with the intrinsic frequency of the LC sensor, the voltage coupled to the LC sensor reaches the maximum. When the frequency of the signal emitted by the readout coil gradually deviates from the intrinsic frequency of the LC sensor, the voltage coupled to the LC sensor gradually decreases from the maximum value. The external readout coil emits a frequency-swept signal in a cyclic manner, so that the magnitude of the voltage value coupled to the LC sensor also changes cyclically within a certain range, thereby controlling the cyclic change of the voltage-controlled capacitance value and making the resonance of the LC sensor also emit cyclic changes within a certain range.

[0014] Step 2: When a partial discharge occurs inside the GIS device, a very high frequency signal with a frequency of 300 MHz to 3 GHz will be generated, and this signal propagates to the LC sensor probe. According to the principle of strong magnetic coupling, when the resonance frequency of the LC sensor is consistent with the partial discharge frequency, the external energy coupled to the LC sensor reaches the maximum value.

[0015] Step 3: The readout circuit detects the signal change situation on the LC sensor through the readout coil. The frequency at the maximum voltage value of the readout signal corresponds to the partial discharge frequency, and at the same time its amplitude reflects the discharge intensity.

[0016] Step 4: After the signal processing circuit processes the voltage signal, voltage amplitude measurement and frequency measurement are realized, and the occurrence of partial discharge can be detected. Then, the frequency and amplitude of the measured partial discharge signal are corresponded to the known partial discharge types to obtain the discharge type of this partial discharge.

[0017] Beneficial effects: By adopting the above technical solutions, the present invention has the following advantages:

[0018] (1) For the GIS partial discharge detection device based on the LC wireless passive sensor of the present invention, compared with other GIS partial discharge detection methods, the size of the sensor of the present invention is very small.

[0019] (2) The present invention can place the sensor probe inside the GIS device to realize wireless signal transmission without opening holes in the GIS box body, which will affect the normal operation of the GIS device.

[0020] (3) With the sensor probe placed inside the GIS box body, the metal box body of the GIS device can be used to shield the noise interference from the external environment, making the system have better anti-interference performance.

[0021] (4) The LC wireless passive technology is adopted to realize the contactless contact mode between the readout circuit and the sensor probe, avoiding the inconvenience caused by installing power supplies, wires, etc. inside the GIS device.

[0022] (5) By changing the resonant frequency of the LC sensor through a variable capacitor, partial discharge detection within a certain frequency range rather than a single frequency can be realized. Description of the drawings

[0023] Figure 1 This is the equivalent circuit diagram of the GIS partial discharge detection device based on the LC wireless passive sensor of the present invention.

[0024] In the figure:

[0025] Readout circuit 1, readout inductance coil 11, signal processing circuit 12;

[0026] LC sensor probe 2, sensor inductance coil 21, varactor diode 22, filter circuit 23. Detailed implementation manners

[0027] The technical solutions of the invention will be described in detail below with reference to the drawings.

[0028] As Figure 1As shown in the figure, the GIS partial discharge detection device based on the LC wireless passive sensor disclosed by the present invention includes a readout circuit 1 and an LC sensor probe 2. The readout circuit 1 is formed by connecting a readout inductance coil 11 and a signal processing circuit 12 in parallel. The LC sensor probe 2 is formed by connecting a sensor inductance coil 21, a voltage-controlled varactor diode 22, and a filter circuit 23 in parallel.

[0029] The LC sensor probe 2 is installed inside the GIS metal box body, and the readout circuit 1 is installed on the rubber sealing ring of the GIS. Signal transmission is carried out between the readout inductance coil 11 and the sensor inductance coil 21 through inductive coupling. The sensor inductance coil 21 can receive the electromagnetic wave signal generated by partial discharge, generate an induced voltage, and transfer this voltage to the readout inductance coil 11 by using strong magnetic coupling. The signal processing circuit 12 can detect the induced voltage across the readout inductance coil 11, thereby detecting the occurrence of partial discharge.

[0030] Its specific working process is as follows:

[0031] (1) The readout inductance coil 11 emits a frequency-swept signal with energy and couples it with the sensor inductance coil 21. When the frequency of the signal emitted by the readout inductance coil 11 is consistent with the intrinsic frequency of the LC sensor, the voltage coupled to the LC sensor reaches the maximum. When the frequency of the signal emitted by the readout inductance coil 11 gradually deviates from the intrinsic frequency of the LC sensor, the voltage coupled to the LC sensor gradually decreases from the maximum value. The readout inductance coil 11 emits a cyclic frequency-swept signal, so that the magnitude of the voltage value coupled to the LC sensor also changes cyclically within a certain range, thereby controlling the cyclic change of the voltage-controlled capacitance value and making the resonance of the LC sensor also change cyclically within a certain range.

[0032] (2) When a partial discharge occurs inside the GIS device, a very high frequency signal with a frequency of 300 MHz to 3 GHz will be generated, and this signal propagates to the LC sensor probe 2. According to the principle of strong magnetic coupling, when the resonance frequency of the LC sensor is consistent with the partial discharge frequency, the external energy coupled to the LC sensor reaches the maximum value.

[0033] (3) The readout circuit 1 detects the signal change situation on the LC sensor through the readout inductance coil 11. The frequency at the maximum voltage value of the readout signal corresponds to the partial discharge frequency, and at the same time its amplitude reflects the discharge intensity.

[0034] (4) After the signal processing circuit 12 processes the voltage signal, voltage amplitude measurement and frequency measurement are realized, and the occurrence of partial discharge can be detected. Then, the frequency and amplitude of the measured partial discharge signal are corresponded to the known partial discharge types to obtain the discharge type of this partial discharge.

Claims

1. A GIS partial discharge detection device based on an LC wireless passive sensor, characterized in that, The device includes: an LC sensor probe (2) and a readout circuit (1); the LC sensor probe (2) includes a sensor inductance coil (21), a voltage-controlled varactor diode (22), and a filter circuit (23) connected in parallel; the readout circuit (1) includes a signal processing circuit (12) and a readout inductance coil (11) connected in parallel; signal transmission is carried out between the sensor inductance coil (21) and the readout inductance coil (11) through inductive coupling. The GIS partial discharge detection method based on the device includes the following steps: Step 1, the readout inductance coil (11) emits a frequency-swept signal with energy and couples it with the sensor inductance coil (21); when the frequency of the signal emitted by the readout inductance coil (11) is consistent with the intrinsic frequency of the LC sensor probe (2), the voltage coupled to the LC sensor probe (2) reaches the maximum. When the frequency of the signal emitted by the readout inductance coil (11) gradually deviates from the intrinsic frequency of the LC sensor probe (2), the voltage coupled to the LC sensor probe (2) gradually decreases from the maximum value; the readout inductance coil (11) emits a frequency-swept signal in a cyclic manner, so that the magnitude of the voltage value coupled to the LC sensor probe (2) also changes cyclically within a certain range, thereby controlling the cyclic change of the voltage-controlled capacitance value and making the resonance of the LC sensor probe (2) emit cyclic changes within a certain range. Step 2, when a partial discharge phenomenon occurs inside the GIS device, a very high frequency signal with a frequency of 300 MHz to 3 GHz is generated, and this signal propagates to the LC sensor probe (2); according to the strong magnetic coupling principle, when the resonance frequency of the LC sensor probe (2) is consistent with the partial discharge frequency, the external energy coupled to the LC sensor probe (2) reaches the maximum. Step 3, the readout circuit (1) detects the signal change situation on the LC sensor probe (2) through the readout inductance coil (11). The frequency at the maximum voltage value of the readout signal corresponds to the partial discharge frequency, and at the same time its amplitude reflects the discharge intensity. Step 4, after the signal processing circuit (12) processes the voltage signal, voltage amplitude measurement and frequency measurement are realized, and thus the occurrence of the partial discharge phenomenon can be detected. Then, the frequency and amplitude of the measured partial discharge signal are corresponded to the known partial discharge types to obtain the discharge type of this partial discharge.

2. The GIS partial discharge detection device based on an LC wireless passive sensor according to claim 1, characterized in that, The LC sensor probe (2) is installed inside the GIS metal box body.

3. A GIS partial discharge detection device based on an LC wireless passive sensor according to claim 1, characterized in that, The readout circuit (1) is installed on the rubber sealing ring of the GIS.

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